1. Field of the Invention
This invention relates generally to apparatus for determining the amount of liquid within a container. More specifically this invention relates to devices for measuring the level of liquid within a sealed, inaccessible container.
2. Description of the Prior Art
Numerous devices exist in the prior art capable of measuring the level of liquid within a sealed, inaccessible container. Generally, the devices consist of a sensing means of some kind within the container (for example, a float) and a means for sending data from the sensing means to a remote location where it would be detected and converted into a useable format representative of the level of liquid within the container (i.e. the number of gallons therein or some other useful parameter).
There is, however, one environment where prior art liquid level gauges are inoperable. In highly radioactive, nuclear environments prior art liquid level gauges fall far short of the characteristics required for operability because of the inherent inability of electronic components of prior art gauges to function at high levels of radioactivity.
Generally, nuclear reactors such as boiling water reactors utilize liquid coolant to maintain temperature control of the nuclear reactions within the reactor. It is desirable for operating personnel to know the level of coolant within the reactor vessel to monitor cooling functions, and it is essential that the level of coolant be known in circumstances where melt-down of nuclear components (control rods, etc.) is feared in order to assess the condition of the interior of the nuclear reactor vessel. However, there is no known liquid level gauge capable of operating within a nuclear reactor to indicate the level of coolant therein. As stated above, the highly radioactive interior of the nuclear reactor vessel destroys all electronic components immediately and renders an electronic liquid level gauge totally useless. Mechanical gauges have been impractical in the nuclear environment in view of the generally compact nature of reactors--offering little room for any mechanical sensing arms or floats, etc.
Thus, there is a need for a liquid level gauge capable of measuring the level of liquid in a radioactive environment within sealed, inaccessible containers.